A power flusher for the brakes costs about $50 and brake fluid $12.
Check out the DIY section here, it is quite easy to do yourself.
If you don't feel up to it, then having the dealer do it once the beginning of summer for the track season would probably cover it.
Some tech forms ask you if they have been flushed within the last 6 months.
also if you are on stock brake pads, please check them between sessions for wear. The stock pads can wear quicker than you would think if you have a lot of heavy braking in your event. They can also fade if they get too hot. Switching to race pads is suggested if you plan to do this more often ( the stock pads really are not made for tracking).
If you are a beginner, you probably won't stress your pads the first few times out.
2011 e92 M3 Monte Carlo Blue ESS 535
2010 Honda FIT
2006 SLK 55 AMG